She’s the newest leading lady.  “Bridgerton” Season 4 star Yerin Ha had a supportive co-star in her on-screen love interest, Luke Thompson. “Because I was working with Luke and he’s already been on the show…I felt like he was my obvious support system, and I was seeing him pretty much every day,” Ha, 28, exclusively told The Post. “I guess I kind of leaned on him, just as a pillar throughout this whole journey.” The “Dune: Prophecy” actress, who is Australian, added that while they were filming,